代码

#include <cstring>
const int bucket = 256;
const int maxn = 100000000;
unsigned b[maxn], cnt[bucket];
void sort(unsigned *a, int n) {
	for (int move = 0; move < 32; move += 8) {
		memset(cnt, 0, sizeof cnt);
		for (int j = 0; j < n; ++j) {
			int x = (a[j] >> move) & 0xff;
			++cnt[x];
		}
		for (int j = 1; j < bucket; ++j) cnt[j] += cnt[j - 1];
		for (int j = n - 1; ~j; --j) {
			int x = (a[j] >> move) & 0xff;
			b[--cnt[x]] = a[j];
		}
		memcpy(a, b, sizeof b);
	}
}

评测结果